IWDFIoRequest2::GetEffectiveIoType method (wudfddi.h)

Article
02/22/2024

[Warning: UMDF 2 is the latest version of UMDF and supersedes UMDF 1. All new UMDF drivers should be written using UMDF 2. No new features are being added to UMDF 1 and there is limited support for UMDF 1 on newer versions of Windows 10. Universal Windows drivers must use UMDF 2. For more info, see Getting Started with UMDF.]

The GetEffectiveIoType method returns the buffer access method that UMDF is using for the data buffers of the I/O request that the IWDFIoRequest2 interface represents.

Syntax

WDF_DEVICE_IO_TYPE GetEffectiveIoType();

Return value

GetEffectiveIoType returns a WDF_DEVICE_IO_TYPE-typed value that identifies the buffer access method that UMDF is using for the I/O request's data buffers.

Remarks

For more information about accessing data buffers and when your driver should use GetEffectiveIoType, see Accessing Data Buffers in UMDF-Based Drivers.

Examples

The following code example shows how an IQueueCallbackWrite::OnWrite callback function can obtain the buffer access method of an I/O request.

VOID
STDMETHODCALLTYPE
  CMyQueue::OnWrite(
    __in IWDFIoQueue *pWdfQueue,
    __in IWDFIoRequest *pWdfRequest,
    __in SIZE_T BytesToWrite
    )
{
    WDF_DEVICE_IO_TYPE currentIoType;

    //
    // Declare an IWDFIoRequest2 interface pointer and obtain the
    // IWDFIoRequest2 interface from the IWDFIoRequest interface.
    //
    CComQIPtr<IWDFIoRequest2> r2 = pWdfRequest;

    currentIoType = r2->GetEffectiveIoType();
...
}

Requirements

Requirement	Value
End of support	Unavailable in UMDF 2.0 and later.
Target Platform	Desktop
Minimum UMDF version	1.9
Header	wudfddi.h (include Wudfddi.h)
DLL	WUDFx.dll